A SQL server recently ran short on disk space and the culprit was the ReportServer_log.ldf file that had grown to 189GB in size… By default this file is allowed to grow to a max size of 2TB (irrespective of available disk space!) and none of the standard maintenance plans, including db backup, reduce its size. Thanks Microsoft…
The solution is to use the SQL Management studio to shrink it (in this example it went from 189GB to 1MB – and no, that is not a typo), set the recovery mode from full (the default) to simple, and you can also change the max size it is allowed to grow to to something more manageable (I set it to 50GB).
A simple step-by-step guide can be found on the Lars Lohmann Blem blog.